code: def load_data(
      self,
      hf_dataset: Dataset,
      input_key: str,
      target_key: Optional[str] = None,
  ) -> Dataset:
      # remove extra columns
      extra_columns = set(hf_dataset.column_names) - {
          input_key,
          target_key,
      }
      hf_dataset = hf_dataset.remove_columns(extra_columns)
  
      if input_key != DataKeys.INPUT:
          hf_dataset = hf_dataset.rename_column(
              input_key, DataKeys.INPUT
          )
  
      if (
          target_key in hf_dataset.column_names
          and target_key != DataKeys.TARGET
      ):
          hf_dataset = hf_dataset.rename_column(
              target_key, DataKeys.TARGET
          )
  
      if flash._IS_TESTING:
          # NOTE: must subset in this way to return a Dataset
          hf_dataset = list(hf_dataset)[:40]
  
      return hf_dataset
  
file_path: lightning-flash/src/flash/text/seq2seq/core/input.py
imports: from typing import List, Optional
  import flash
  from flash.core.data.io.input import DataKeys, Input
  from flash.core.data.utilities.loading import load_data_frame
  from flash.core.data.utilities.paths import PATH_TYPE
  from flash.core.utilities.imports import _TOPIC_TEXT_AVAILABLE, requires
label_desc: Use image node_id 1 for calling the Seq2SeqInputBase obj's underlying member method code with example usage: obj.load_data(hf_dataset, input_key, target_key) and returns: hf_dataset